Glad I am not the only one who remembers these, I can now distinctly remember the clicking sound they made now you mentioned it, takes me right back.
Since this thread stirred up my interest I have dismantled and rebuilt my Sturmey Archer Dynohub. All I can say is I am impressed with their performance, it was manufactured in July 1959 and appears to perform exactly as it did on the day it was made.
I cleaned up the dirt and rust from the internals, and used a piece of 70mm diameter steel to push the armature out of the magnet and act as a keeper to maintain the magnetism. I replaced the corroded ball bearings with new ones from a local cycle shop that still has the odd spare part for them, still in Sturmey Archer boxes that have sat on the shelf since the 1950's.
It produces power almost the instant it is rotated. I test ran it on my lathe up to 300 RPM with around 18 volts, and it continues to produce power as the speed is wound down until it comes to a stop.
There is quite a bit of magnetic drag from the 20 pole ring magnet, which makes it feel notchy and lumpy as it is rotated, as if the whole thing and bearings are full of grit despite being assembled spotlessly clean with fresh grease.
I think it will suite the Red Wing engine and should have a little flywheel affect as well.
